The works of Karl Leonhard Reinhold (17571823) were a major factor in the development of post-Kantian philosophy, yet his exact contribution is still under discussion. This book investigates how Reinholds background in Enlightenment influenced his reception of Kants critical philosophy. From his pre-Kantian efforts up to the point where he began distancing himself from the master, Reinholds own philosophical development takes center stage. This development, rather than critical philosophy, was the main ingredient of Reinholds contribution to post-Kantian philosophy.